The preterminal breaths during asphyxiation termed "asphyxial gasps" are believed to be an indication of impending death in the fetus and may function as a mechanism of spontaneous recovery ("auto resusitation") from prolonged apneic spells in infants and adults. The proposed research is designed to investigate the neural regulation of asphyxial gasping in an animal model (rabbits). The influence of maturation, neural stimulation and environmental factors on aspects of gasping (duration, frequency force, etc.) will be examined. The independent activity of the various respiratory muscles during gasping will be evaluated.